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UNITED STATES DEPARTMENT OF AGRICULTURE 

BULLETIN No. 350 



Contribution from the Bureau of Plant Industry 
WM. A. TAYLOR, Chief 




ssJr&mrL 




sv&'^ru 



Washington, D. C. 



PROFESSIONAL PAPER 



March 10, 1916 



THE UTILIZATION OF CHERRY BY-PRODUCTS. 

By Feank Kabak, 
Chemical Biologist, Drug-Plant and Poisonous-Plant Investigations. 



CONTENTS. 



Introduction 

Relation of the cherry to sweet and 

bitter almonds and allied plants 

Commercial importance of cherries 

Accumulation and disposal of by- 
products 



Page. 



Page. 
Commercial products obtainable from 

cherry pits 4 

Commercial products obtainable from 

cherry juice 22 

Summary 24 



INTRODUCTION. 

The rapid development of the fruit-packing industry in the United 
States within recent years has had a tendency to direct the attention 
of packers to the large accumulations of by-products which at pres- 
ent are valueless because of their lack of utilization. The nature of 
these waste products differs, according to the fruit from which they 
result. In most cases some portion of the fruit is discarded because 
it has no further use. Often it is the exterior portion, but in many 
cases, especially with fruits which require pitting, the waste prod- 
ucts consist of pits or seeds which must be removed before canning. 

In previous publications of the Department of Agriculture 1 atten- 
tion has been called to the enormous quantities of raisin seeds and 
peach and apricot pits which may be made to yield valuable com- 
mercial products, and already some manufacturers are turning their 
attention to these waste products with a view to their profitable 
utilization. 

More recently the attention of the writer has been called by fruit 
packers to the waste which results from the cherry-packing industry 
of the North Atlantic, North-Central, and Western States. This is 

1 Rabak, Frank. Peach, apricot, and prune kernels as by-products of the fruit industry 
of the United States. U. S. Dept. Agr., Bur. Plant Indus. Bui. 133, 34 p., 1908. 

The utilization of waste raisin seeds. U. S. Dept. Agr., Bur. Plant Indus. Bui. 

276, 36 p., 3 fig., 1913. 

19348°— Bull. 350—16 1 



(boitograph 



2 BULLETIN 350, U. S. DEPAKTMEXT OF AGRICULTURE. 

material which has not only been discarded as valueless, but has 
actually been a source of expense, due to charges for hauling it away. 
New York, Michigan, Wisconsin, and California produce the bulk 
of the cherries grown for canning purposes, and in preparing the 
fruit for canning large quantities of pits and juice accumulate. 

RELATION OF THE CHERRY TO SWEET AND BITTER ALMONDS AND 

ALLIED PLANTS. 

The cherry belongs to the natural order Drupaceae, which includes 
a number of our most important fruits, such as peaches, apricots, 
and prunes. It is a native of Asia Minor and has been introduced 
into Europe and the United States. 

The fruit of the red sour cherry furnished the material for the 
following investigation, since it is mostly the fruit of this variety 
which is pitted for commercial use. The red sour cherry is designated 
botanically as Prunus cerasus L. Among the principal varieties 
grown commercially are the Montmorency Ordinaire, the Richmond, 
and the English Morello, the first named being the most important 
variety and producing the bulk of the fruit grown, 

The peach, known botanically as Amygdalus persica L., the apricot, 
Amygdalus armeniaca L., and the prune, Prunus domestica L., are 
closely related to the cherry, as are also the sweet almond, Amygdalus 
com/munis dulcis DC. and the bitter almond, Amygdcdus communis 
amara DC. All of these species, including the cherry, produce drupa- 
ceous fruits which, although of somewhat different sizes and shapes, 
possess the same general characteristics. 

The kernels of both the sweet and bitter almonds yield products of 
commercial value, as do also the kernels of the peach, apricot, and 
prune. From the standpoint of chemical composition the kernels of 
these various species, and also of the cherrj^, are for the most part 
identical. All consist principally of a fatty oil and protein, with 
smaller quantities of sugar, mucilage, and the glucosid amygdalin. 

It is generally known that bitter almonds yield two important com- 
mercial products, namely, fixed oil and volatile oil. The fixed oil is 
obtained from the kernels by expression, while the volatile oil is the 
result of a chemical process induced by the action of the enzym emnl- 
sin upon the glucosid amygdalin. It has been found that peach, 
apricot, and prune kernels also yield oils very similar to those obtained 
from bitter almonds. 1 The present investigation has shown that 
cherry kernels likewise are capable of yielding similar oils. 

COMMERCIAL IMPORTANCE OF CHERRIES. 

As has been stated, the pitting and canning of cherries is restricted 
almost entirely to the red sour cherries. A variety of sweet cherry, 

1 Rabak, Frank, op. oil., 1908. 

D.'Cf D. 
MAfi ,; 27 1916 



THE UTILIZATION OF CHERRY BY-PRODUCTS. 3 

the Napoleon (syn., Royal Ann) , is cultivated extensively in Califor- 
nia, and to a lesser degree in Oregon and Washington. This is used 
partly to supply the demand for the bottled cherries of commerce 
known as the maraschino cherries. Most of the cherries used for this 
purpose, however, are imported from Spain and Italy. These are 
pitted and bottled in the United States and constitute an important 
article of commerce. A large accumulation of pits results from the 
packing of the imported cherries, and the present investigation has 
been extended to include this waste product, as well as the waste 
resulting from domestic cherries. 

The extent of the cherry-packing industry is indicated in the agri- 
cultural statistics of the States mentioned. According to the Thir- 
teenth Census of the United States, the quantity of cherries grown 
in New York in 1909 was 271,597 bushels, in Michigan 338,945 bushels, 
and in Wisconsin 81,340 bushels, making a total of 691,882 bushels, 
or 20,756 tons. The quantity grown at the present time is doubtless 
considerably in excess of these figures. Approximately 80 per cent 
of the crop is canned, which is equivalent to 553,506 bushels, or 16,605 
tons. The total output of the California orchards in 1909 was 501,013 
bushels, or about 15,000 tons. 

Accurate figures showing the total quantity of cherries pitted an- 
nually are not available. Approximate figures, however, were ob- 
tained by correspondence and by consultation with the principal pack- 
ers in the various canning sections. The average annual importa- 
tion of maraschino cherries from Italy and Spain, as calculated from 
the quantity of pits which result, is about 2,500 tons. 

ACCUMULATION AND DISPOSAL OF BY-PRODUCTS. 

Two by-products of the cherry industry, the pits and the juice, are 
at present entirely wasted. From the standpoint of commercial 
utilization the pits constitute the larger and more important of these 
waste products. 

It has been estimated that about 15 per cent of the cherries consists 
of pits. Since definite information regarding the total quantity of 
cherries pitted was unavailable and since the quantity pitted is de- 
pendent entirely upon the crop of each season, only approximate 
figures regarding the total output of waste pits are presented. 

The figures given were obtained by interviews and correspondence 
with 23 packers in New York, 6 in Michigan, and 3 in California, 
who estimated the quantity of waste pits in 1914 as follows: New 
York, 800 tons; Michigan, 200 tons; and California, 400 tons. The 
total output was probably somewhat greater, as several packers failed 
to supply estimates. Wisconsin is rapidly increasing the acreage of 
cherries and, as predicted by growers, will probably produce several 



4 BULLETIN 350, TJ. S. DEPARTMENT OF AGRICULTURE. 

hundred tons annually. Smaller quantities are also available in New 
Jersey and Pennsylvania. 

From the figures given by the packers it would appear that 1,600 
tons is a conservative estimate for the total quantity of cherry pits 
that become available each year. This quantity will most likely in- 
crease, owing to the increasing acreage. 

The cherry juice which results from this industry accumulates in 
very large quantities. According to one prominent packer the quan- 
tity of juice is estimated at about 70 gallons per ton of cherries. Cal- 
culated on the quantity of cherries pitted, it is estimated that the ap- 
proximate output of juice is 112,000 gallons annually. At the present 
time this by-product is entirely wasted, although several packers have 
attempted to find some use for it. 

The pits of the imported cherries have also been discarded, and 
often at considerable expense. About 650 tons may be considered as 
the annual output of this waste. 

The writer was informed by nearly all the packers consulted that 
much thought has been given to a possible utilization of the large 
quantities of waste material and that great benefit would result and 
an added stimulus be given to this important branch of the fruit 
industry if a profitable utilization of the waste products could be 
accomplished. 

Actuated, therefore, by the requests of many packers and by actual 
observation of the large quantities of pits and juice which accumu- 
late at the packing plants, the investigation herein described was 
undertaken. 

COMMERCIAL PRODUCTS OBTAINABLE FROM CHERRY PITS. 

Because of the relationship of the cherry to the sweet and bitter 
almonds and to the peach, apricot, and prune, it was not unreasonable 
to suppose that products could be obtained from the pits of the 
cherry similar to those obtained from the other fruits mentioned. 
Fixed and volatile oils are at present manufactured from almonds 
and from peach and apricot kernels. The oils from these various 
kernels are practically identical in character and may be used for 
similar purposes; in fact, they are so nearly alike that much of the 
almond oil of commerce has been obtained from peach and apricot 
kernels. The composition of the kernels from cherry pits is such as 
to admit of the extraction of fixed and volatile oils, both possessing 
the general characteristics of almond oils. 

The pits of the imported cherries present a somewhat different prob- 
lem, due to the treatment of the fruit before importation. At the 
time these cherries are picked the kernels contain presumably the 
same constituents as the domestic cherries. The composition is not a- 



THE UTILIZATION" OF CHERRY BY-PRODUCTS. 5 

bly altered, however, by the processes involved in packing. Briefly, 
the fruit receives the following treatment : When ripe it is picked and 
placed in trays, and then subjected to the bleaching action of sulphur 
dioxid, which changes the red color of the fruit to a pale yellow. After 
bleaching, it is packed in a 3 per cent salt brine in casks having a 
capacity of 350 pounds, in which containers it is imported, the cherries 
remaining in the brine for about four months. 

In bottling the cherries the first step consists in washing them with 
successive portions of fresh water until all the salt is removed. The 
cherries are then pitted by hand, women being employed for this 
operation. After pitting, the fruit is packed in the bottles by hand, 
and hot sirup is poured over it, together with an artificial red color- 
ing matter and a small quantity of bitter- almond oil, the latter being 
added to impart the cherry flavor. 

Upon examining the kernels of the pits which were removed from 
these cherries before bottling, it was observed that when the kernels 
were crushed in the mouth no volatile oil was apparent. It is quite 
probable that the action of the sulphur dioxid and the salt brine exerts 
a detrimental influence upon the glucosid contained in the kernel. 
The fact that no bitter-almond taste developed was conclusive evi- 
dence that the amygdalin had been destroyed or its hydrolysis im- 
paired by the treatment the fruit had received. However, a fixed oil 
was found to be present in the kernels and its quality was not seriously 
impaired, as will be shown later. 

The juice from the domestic cherries is extremely acid in taste, but 
after neutralization of the acid considerable sugar was noted. The 
preparation of alcohol from the waste juice and the possibility of re- 
ducing the juice to a sirup were considered. It was thought probable 
also that by means of some jelling medium the juice might be used 
for making jelly. 

Attention may also be directed to the meal which results after the 
extraction of the fixed and volatile oils from the pits and kernels. 
This meal is rich in nutritive constituents and should find a useful 
outlet in commerce. 

Briefly summarizing : A number of products may be obtained from 
the pits and kernels of cherries and from the juice, which, as will be 
shown, may prove of commercial importance. 

FIXED OIL. 

METHODS OF EXTRACTION. 

The extraction of a fixed oil from seeds is usually accomplished 
by one of two methods : The use of hydraulic pressure or of volatile 
solvents. Both methods have a general application. 

Volatile solvents are used in many instances, especially in the case 
of seeds which are more or less deficient in oil. In all cases the sol- 



6 BULLETIN 350, U. S. DEPARTMENT OF AGRICULTURE. 

vents used are such as will readily dissolve the oil. Among those em- 
ployed are gasoline, ether, benzene, petroleum ether, chloroform, car- 
bon bisulphid, and carbon tetrachlorid. Apparatus of the continuous- 
extraction type is usually employed. This admits of the recovery of 
the solvent and minimizes the loss of the solvent. It has been reported 
that recent improvements in method and apparatus have made this 
process cheaper than the pressure method. The solvent can be entirely 
removed from both the oil and the residue. It is also held that by the 
employment of this process various kinds of material can be treated 
in the same apparatus. The expense of operating is also said to be 
less than the pressure method. 

The color of oils extracted by solvents is often very dark and it is 
necessary to remove it, but this can usually be accomplished with no 
great difficulty. 

The solvents perhaps most frequently employed, because of their 
comparatively low price, are benzene, petroleum ether, gasoline, and 
carbon tetrachlorid. Of these, carbon tetrachlorid has within recent 
years become very popular, not only because of its cheapness but 
because- of its noninflammability and less volatile nature, thus reduc- 
ing the danger from fire and minimizing the loss from evaporation. 
According to a recent report 1 benzine is used for the extraction of 
soy-bean oil in a new mill of the South Manchurian Railway Co. at 
Dairen, this mill having a capacity of 80 tons daily. 

Hydraulic pressure is perhaps more universally used than any 
other method and especially in the case of seeds having a high per- 
centage of oil. This method is not practicable, however, with seeds 
of low oil content, because the resulting press cake retains a consider- 
ble percentage of the oil, and this would materially affect the total 
yield. Seeds which contain as high as 30 to 50 per cent of oil are 
best manipulated by extraction under pressure from hot meal or with 
heated plates, a maximum percentage of oil being thereby obtained. 
As a general rule, the quality of an oil obtained by hydraulic pres- 
sure excels that obtained by volatile solvents, cold pressure produc- 
ing even better quality than hot pressure. Oils obtained by the pres- 
sure method invariably contain less impurities than those extracted 
by solvents, and therefore require less refining. 

Suitable presses for extracting fixed oils are on the market, all 
embodying the same general principle. Continuous extractors, pref- 
erably of copper, are also obtainable from American manufacturers, 
especially manufacturers of pharmaceutical machinery. 

EXTKACTION OF OIL FROM THE PITS BY SOLVENTS. 

A quantity of dry pits was finely ground in a drug mill and intro- 
duced into a continuous-extraction apparatus fashioned after the 

1 Parlett, II. G. New bean-oil extracting mill at Dairen on the benzine system. In 
Bd. Trade Jour. [London], v. 86, no. 92:5, p. 385, 1914. 



THE UTILIZATION OF CHERRY BY-PRODUCTS. 7 

Soxhlet extractor. Extraction was made with ether and continued 
until the material was completely exhausted. By this process a yield 
of 8.3 per cent of a pale-brown fixed oil was obtained. By the same 
process the pits from the imported cherries yielded 4.5 per cent of a 
deep-brown, rancid-smelling oil. 

The crude oil thus obtained was not only deeply colored but pos- 
sessed a characteristic odor of rancidity, due to the presence of free 
volatile fatty acids. In order to free the oil of the objectionable 
color and odor it was subjected to the following refining process: 
The oil was introduced into a flask and live steam was conducted 
through the mass until the distillate which contained the free vola- 
tile acids possessed no appreciable odor and was no longer acid to 
litmus. While hot, the oil was separated from the water in the flask 
by means of a separatory funnel, treated with kaolin (fuller's earth), 
and the mass filtered through filter paper in a hot filtration funnel. 
The filtered oil was pale golden yellow in color, with a distinctly 
nutlike taste and with no suggestion of rancidity. 

EXTRACTION OF OIL FROM THE KERNELS BY PEES SURE. 

Hydraulic pressure was not found applicable to the pits, because of 
the low yield of oil. It was necessary, therefore, to crack the pits 
and remove the kernels. This was accomplished by slowly feeding 
the pits into a mill having vertical grinding plates set to grind very 
coarsely, so that a mere cracking of the shells resulted without crush- 
ing the kernels. The cracked pits were first put through a round- 
hole sieve with openings sixteen sixty-fourths of an inch in diameter 
and then through another sieve with openings of thirteen sixty- 
fourths of an inch. This removed the coarser parts of the shells. 
A final separation was made by passing the material through a " wild- 
oat " sieve with oblong meshes measuring seven sixty-fourths by one- 
half of an inch. The last screening effected a reasonably complete 
separation of the kernels from the shells. 

It is very important that the mill be fed with a slow, continuous 
stream of pits, and care must be exercised in order not to crush the 
kernels, otherwise they are apt to separate into halves and the halves 
pass through the final sieve. By this process 28 per cent of the pits 
was found to consist of kernels. 

The laboratory press available for the extraction of the oil from the 
kernels was not entirely adequate for obtaining the best results. A 
pressure of 2,750 pounds to the square inch was applied to the finely 
ground kernels, the expression being conducted in the cold. A yield 
of 21 per cent of a pale golden yellow oil, with a pleasant nutlike 
odor and taste, was thus obtained. With a commercial hydraulic 
press of the latest type, equipped for hot expression, a much higher 
yield would undoubtedly result. Working on a commercial scale 



8 



BULLETIN 350, U. S. DEPARTMENT OF AGRICULTURE. 



with an efficient hydraulic press or oil expeller, a yield of at least 30 
$er cent of oil should be obtained. 

For the purpose of comparing the yield and general characteristics 
of the oils obtained from cherry kernels by solvent and by expression 
with oils from related kernels, Table I was compiled. 



Table I. — Yield and physical properties of crude and refined cherry oils com- 
pared with other related oils. 







Spe- 


Index 










Source of oil. 


Yield 
of oil. 


cific 

gravity 

at 23° 

C. 


of re- 
fraction 
at 23° 
C. 


Congealing 
point. 


Color. 


Odor. 


Taste. 


Cherry pits (red 
















sour cherries): 


P.ct. 














Crude 


8.3 


0. 9204 


1.4697 


Turbid at -8° 
C; almost 
solid at — 12° 
C. 

Turbid at —8° 


Pale brown. . . 


Slightly rancid 


Slightly acid, 
fatty ,slightly 
bitter. 


Refined 




.9171 


1.4700 


Pale golden 


Bland, fatty... 


Bland, fatty, 










C; nearly 


yellow. 




nutlike. 










solid at— 15° 
C. 
Turbid at -13° 








Cherry kernels 


132 


2 . 9150 


1. 4727 ' 


Pale golden . . . 


Pleasant, nut- 


Bland, nutty, 


(red sour cher- 








C; semisolid 




like. 


agreeable. 


ries). 








at-18°C. 








Cherry pits(im- 
















ported. cher- 
















ries): 
















Crude 


4.5 


.9302 


1. 4582 


Semisolid at 
-11° C. 


Peep brown... 


Patty, slightly 
rancid. 


Fatty, slightly 
acid. 


Refined 




.9276 


1.4790 


Semisolid at 


Pale brown 


Bland, fatty. . . 


Bland, fatty. 










-16° C. 




Cherry kernels 


150 


.9156 


1.4775 


do 


Peep straw 


Agreeable, 


Fatty and nut- 


(imported 












fatty. 


like. 


cherries). 
















Peach kernels 3 . 


39.5 


* . 9166 




Solidifying 
point below 


Yellowish 


Fatty, nearly 


Bland, fatty, 












odorless. 


nutty. 










-20° C.5 








Apricot ker- 


40 


* . 9168 


61.4712 


-20°C.e 


Straw colored . 


Slightly fatty, 


Fatty and nut- 


nels. 3 












nearly odor- 
less. 
Patty, nutlike. 


ty. 


Prune kernels 3 . 


35 


* . 9164 




-10° C 7 


Golden yellow. 


Bland, nutty, 
















slightly 
















sweet. 


Sweet almonds 


49 


< . 9162 




-21°C.8 


Light yellow . . 


Nearly odor- 


Nut like and 


(Spain). 3 












less, fatty. 


fatty. 


Bitter almonds 


42.3 


4.9158 


° 1. 4705 


-10°C.8 




do 


Bland and 


(Italy). 3 














fatty. 



1 By ether extraction. 

2 Specific gravity and other physical constants represent expressed oil of cherry kernels. 

3 Rabak, Frank. Peach, apricot, and prune kernels as by-products of the fruit industry of the United 
States. U. S. Dept. Agr., Bur. Plant Indus. Bui. 133, p. 15, 1908. 

* At 25° C. 

6 Lewkowitsch, J. Chemical Technology and Analysis of Oils, Fats, and Waxes, v. 2, p. 232. London, 
1909. 

6 At 20° C, see Lewkowitsch, J., op. cit., p. 228. 

7 Lewkowitsch, J., op. cit., p. 230. 

8 Lewkowitsch, J., op. cit., p. 235. 

9 At 25° C, see Lewkowitsch, J., op. cit., p. 236. 

An examination of Table I shows that the specific gravity of the 
refined oil from the pits and of the expressed oil from the kernels 
corresponds very closely with that of the oils from the other kernels 
enumerated, thus indicating a like composition of all the oils, since 
the specific gravity of fixed oils is a property which is influenced 
largely by its composition. The high specific gravity of the crude 
pit oil is attributed to the presence of impurities, largely in the form 
of free fatty acids, which later were removed in the refining process. 



THE UTILIZATION OF CHERRY BY-PRODUCTS. 



9 



The refractive index appears likewise to be affected by the pres- 
ence of free fatty acids as impurities. The crude oils are seen to 
possess a lower refractive index than those which have been refined 
and which therefore contain less impurities. The refractive prop- 
erty of the refined oils corresponds very closely with that of the 
other oils included in Table I. 

The congealing point is a property which is affected by differences 
in composition. Oils of the same kind, whether crude or refined, 
often differ in the congealing point, as is shown by the oils from the 
pits of both the domestic and the imported cherries. The refined 
cherry oil compares favorably in this respect with the other oils 
tested. 

No marked difference is observed in the color, odor, or taste of the 
various oils except that the crude oils are slightly darker and have 
a less agreeable odor and taste than the other oils. 

For the purpose of making a further comparison it was deemed 
advisable to determine the so-called chemical constants (the acid, 
saponification, and iodin values), which are shown in Table II. 

Table II. — Chemical constants of cherry oils compared with various other fruit- 
kernel oils. 



Source of oil 



Cherry pits (red sour 
cherries): 

Crude 

Refined 

Cherry kernels (red sour 
cherries) cold pressed 2 
Cherry pits (imported 
cherries): 

Crude 

Refined 



Free fatty 
acids. 


Sa- 

poni- 

fica- 

tion 

value. 


Iodin 
value. 


Acid 
value. 


Cal- 
cu- 
lated 

as 
oleic 
acid. 


21.5 
15.1 

6.2 

22.1 
18.4 


P.ct. 

10.90 
2.58 

3.13 

11.10 
4.10 


189.2 
186.4 

187.6 

185.2 
189.8 


101.7 
102.4 

106.9 

110.3 
111. 4 



Source of oil. 



Cherry kernels (import- 
ed cherries) 

Peach kernels 3 

Apricot kernels 3 

Apricot kernels (same as 
above, 1 year old) 

Prune kernels 3 

Sweet almonds (market 
sample) 3 

Bitter almonds 3 



Free fatty 
acids. 



Acid 
value. 



3.5 

.83 
.75 

13.3 
1.9 

3.5 
1.7 



Cal- 
cu- 
lated 

as 
oleic 
acid. 



P.ct. 

1.76 
.41 
.38 

6.68 
.95 

1.76 

.86 



Sa- 

poni- 

fica- 

tion 

value. 



188.5 

187 

203 

180 
160 

193 

188 



Iodin 
value. 



108.2 

110 

107 

118 
105 

107.3 
106.3 



1 Acid number determined after standing 6 months. 

2 Kernels obtained from pits about 1 year old. 

3 Rabak, Frank. Peach, apricot, and. prune kernels as by-products of the fruit industry of the United 
States. U. S. Dept. Agr., Bur. Plant Indus. Bui. 133, p. 16, 1908. 

Before discussing the data in Table II it should be mentioned that 
the amount of free fatty acids in an oil is wholly dependent upon the 
age of the oil or of the material from which it is extracted. Freshly 
expressed or extracted oils from fresh material show but a trace of 
free acids, often less than 1 per cent. Most fatty oils are unstable 
as regards the liberation of free fatty acids, the quantity increasing 
with the age of the oil. 

The crude oils from the cherry pits show a high acid content, 
which, however, was largely reduced in the process of refining. The 
1934S — Bull. .°>")0— 16 2 



10 BULLETIN 350, U. S. DEPARTMENT OF AGRICULTURE. 

cold-pressed oil from the kernels of the domestic cherries, although 
examined immediately after extraction, contained considerable free 
acidity. This was doubtless due to the fact that the kernels were 
taken from pits which had been kept in the laboratory for about a 
year. As a general rule, oil from old seeds is high in acid content. 

The acidity of the oil from the kernels of the imported cherries 
was considerably lower, due possibly to freshness of the kernels. 

With two exceptions, the related oils included in Table II are low 
in acidity, due to the fresh condition of the oil when examined. Of 
the two exceptions, one of the oils was a year old before the deter- 
mination of the free acidity was made, and the other was a market 
sample, the age of which was not known. 

The saponification and iodin values of the cherry oils, which values 
are a criterion of the composition, agree quite closely with each other 
and compare favorably with the other oils, only an occasional vari- 
ation occurring. 

From the standpoint of general chemical composition, therefore, 
the refined oil from the cherry pits and the expressed oil from the 
kernels are very similar to almond oils and to the oils from peach, 
apricot, and prune kernels. 

CHEMICAL EXAMINATION OF THE FIXED OIL. 

The general nature of the fixed oil having been determined, a more 
detailed analysis was made in order to obtain information bearing 
on the composition of the oil and to note the effect of refining on the 
more important properties. 

Besides the acid, saponification, and iodin values, the following 
additional constants were determined, according to the method rec- 
ommended by the Association of Official Agricultural Chemists : 1 

The volatile acids, consisting of the glycerids of such acids as butyric, valeri- 
anic, caproic, etc., were determined and expressed as the Reichert-Meissl num- 
ber, which is a measure of the volatile acids expressed in cubic centimeters of 
decinormal alkali required to neutralize the volatile acids contained in 5 grams 
of oil. 2 

The soluble and insoluble acids were determined, the former representing the 
percentage of soluble acids calculated as butyric acid and the latter the per- 
centage of insoluble fatty acids (Hehner value). 8 

The acetyl value, which is a measure of the glycerids of hydroxy fatty acids, 
was determined largely for comparative purposes. 4 

Likewise the unsaponifiable matter, which is a variable characteristic, was de- 
termined. 5 The percentage of unsaponifiable matter in a fixed oil is regulated 
largely by the presence of variable quantities of an alcoholic substance, phytos- 
terol, and other substances, such as coloring matter and waxlike compounds. 

1 Wiley, II. W., ed. Official and provisional methods of analysis, Association of Official 
Agricultural Chemists. As compiled by the committee on revision of methods. TJ. S. 
Dept. Agr., Bur. Chem. Bui. 107 (rev.), 272 p., 13 fig., 1908. 

2 Wiley, II. W., op. cit., p. 139. 

3 Wiley, II. W., op. cit., p. 138, 139. 

4 Wiley, II. W., op. cit., p. 142. 
6 Wiley, II. W., op. cit, p. 144. 



THE UTILIZATION OF CHERRY BY-PRODUCTS. 



11 



The insoluble acids comprise the largest portion of all fixed oils, 
and these were studied in detail by resolving them into the solid and 
liquid acids of which they are composed. The nature of the solid 
and liquid acids of an oil is of importance, since upon the percentage 
of these respective acids depends largely the application of the oil in 
commerce, whether it can be used for edible purposes, for soap mak- 
ing, or as a drying oil. 

The separation of the solid and liquid acids was accomplished by 
the lead-ether method. 1 The efficacy of this method depends upon 
the solubility in cold ether of the lead salts of the liquid acids and the 
insolubility of the same salts of the solid acids. After the separation 
of the solid and liquid acids the physical and chemical properties of 
each were determined, from which the approximate composition of 
the oils was deduced. 

The foregoing methods were applied to the crude oil which was ex- 
tracted from the pits of the domestic cherries by ether ; also to the re- 
fined oil from the pits and to the expressed oil from the kernels. The 
results of these determinations are given in Table III. 



Table III. — Chemical characteristics of the oils from cherry pits and kernels. 



Source of oil. 


Volatile 
acid, or 

Reichert- 
Meissl 

number. 


Soluble 
acids (cal- 
culated as 

butyric 
acid). 


Insoluble 
acids. 


Acetyl 
value. 


Unsaponi- 
fiable. 


Cherry pits (red sour cherries): 

Crude 


Per cent. 
6.32 
3.665 
4.72 


Per cent. 
1.22 
.473 
.469 


Per cent. 
92 
92.5 
92.8 


20.3 
3.45 
12.67 


Per cent. 
2.45 


Refined 


1.12 


Cherry kernels (red sour cherries) 


.44 







The data in Table III clearly show the effect of the refining process 
upon the composition of the oils. The refined oil from the pits more 
nearly approaches the expressed oil from the kernels. As would be 
expected, the content of volatile x acids is highest in the crude oil from 
the pits, while the refined oil differs only slightly in this respect from 
the kernel oil. 

The percentage of soluble acids, calculated as butyric acid, de- 
creases much the same as the volatile acids. The crude pit oil shows 
1.22 per cent of butyric acid, which in the refined oil is reduced 
to 0.473 per cent. The refined oil nearly corresponds with the 
kernel oil. 

The insoluble acids, which constitute by far the greatest portion 
of the oil, show only slight differences in the three oils. 

The acetyl values given represent the true values after correction 
for the volatile acids. If indicated without correction they would 
be too high by the amount of volatile acids present. Here, also, is 



1 Wiley, II. W., op. cit.. p. 142, 145. 



12 



BULLETIN 350, U. S. DEPARTMENT OF AGRICULTURE. 



seen the favorable effect of the refining process. The acetyl value 
of 20.3 in the crude pit oil was reduced to 3.45 in the refined oil. The 
kernel oil, however, shows a considerably higher acet} 7 l value than 
the refined oil from the pits. This is due to the fact that the kernels 
were taken from pits which were not in fresh condition. 

The amount of unsaponifiable matter in an oil depends largely 
upon the amount of coloring matter and waxlike substances con- 
tained in it. Therefore, the crude oil would be expected to show the 
highest percentage, which is substantiated by the results obtained. 

As previously stated, the insoluble acids are most important fac- 
tors in determining the quality and usefulness of an oil. Therefore, 
the physical and chemical constants of these acids were determined, 
and the results are presented in Table IV. For the purpose of com- 
parison, the known constants of a number of related oils are also in- 
cluded in Table IV. 



Table IV. — Physical and chemical constants of insoluble acids of oils from 
cherry pits and kernels and from other fruit kernels. 



Source of oil. 


Color. 


Odor. 


Taste. 


Spe- 
cific 
gravity 
at25°C 


Refrac- 
tive 
index 
at25°C. 


Congeal- 
ing point. 


Neu- i 

trali- j Iod'n 
zation lvalue, 
value. 


Cherry pits: 
Crude 

Refined . . 

Cherry ker- 
nels. 

Peach ker- 


Pale brown. 
do 

Pale straw . . 


Rancid, fatty. 

Slightly ran- 
cid, fatty. 

Nut like, slight- 
ly rancid. 


Bland, fatty, 
hitter. 

Sweetish,fatty, 
hitter. 

Sweetish, fatty, 
slightly hit- 
ter. 


0. 9019 
.9137 
.9092 


1.4635 
1.4641 
1.4635 


° C. 
12 to 11 

12. 5 to 12 

13.5 to 13 

13. 5 to 13 


192.4 
179.7 
180.8 

205 
to 

209.9 
194 

200.4 

204 


99.9 
93.7 
92.8 

94.1 


nels. 1 

Apricot ker- 
nels. 2 

Prune ker- 








.9195 




to 

101.9 
99.4 










13 to 12 

11.8 

to 

11.3 


to 

103.8 
95.7 


nels.3 
Almond ker- 










1. 44(U 


to 

102 
93.5 


nels. 4 










10 

96.5 



1 Lewkowitsch, J. Chemical Technology and Analysis of Oils, Fats, and Waxes, vol. 2, p. 232. London, 
1909. 

2 Specific gravity at 15° C, see Lewkowitsch, J., op. cit., p. 22^. 

3 Lewkowitsch, J., op. cit., p. 230. 

* Refractivo index at 60° C, see Lewkowilsch, L, op. cit., p. 237. 

Only slight differences in the physical properties — color, odor, and 
taste — of the insoluble acids are noted in the cherry oils. Data on 
these points were not available for the other oils. The specific grav- 
ity, refractive index, and congealing points of the insoluble acids of 
cherry oils compare favorably with the same constants of the related 
oils. The neutralization values differ somewhat from those of the 
related oils, with the exception of the crude pit oil. This indicates a 
slightly different composition from the standpoint of fatty acids. 
The iodin value, which indicates the content of unsaturated acids. 



THE UTILIZATION OF CHERRY BY-PRODUCTS. 



13 



compares favorably with the related oils. General factors, such as 
the age of the oil and the time intervening between the separation of 
the insoluble acids and the determination of the constants, would tend 
to modify the results obtained. 

For the purpose of comparison, the physical and chemical char- 
acteristics of the solid and liquid acids, after separation from the 
insoluble acids, were determined, and the results are given in Table V. 

Table V. — Physical and chemical constants of solid and liquid acids of oils 

from cherry pits and kernels. 





Solid acids. 


Liquid acids. 


Source 
of oil. 


Yield. 


Description. 


Melt- 
ing 
point. 


Neu- 
traliza- 
tion 
value. 


Yield. 


Description. 
4- 


Spe- 
cific 

gravity 
at 

23° C 


Re- 
fractive 
index 

at 
25° C 


Neu- 
traliza- 
tion 
value. 


lodin 
value. 


Cherry 


Per 








Per 












pits: 


cent. 




° a 




cent. 












Crude... 


6.27 


White, waxy 
mass, fatty 
odor. 


51 


197.2 


84 


Golden - yellow 
liquid, with 
nutlike odor, 
and sweet, 
fatty taste. 


0. 8917 


1. 4603 


185.1 


98 


Refined . 


8.94 


White, waxy 
mass, with 
tallow like 
taste. 


49.0 


192.3 


83.2 


Brownish oil, 
liquid, with 
nutlike odor, 
and sweet 
and bitter 
after taste. 


.9028 


1. 4643 


188.2 


108.7 


Cherry ker- 


8.96 


White, waxy 


49.5 


205.1 


82.8 


Straw colored, 


.8941 


1. 4617 


190.6 


114 


nels. 




mass, with 
fatty odor, 
tallowy 








with slightly 
rancid odor 




















and sweetish 














taste. 








bitter taste. 











From Table V it will be observed that the solid acids constitute 
only a small portion of the cherry oils. The crude oil from the pits 
shows a considerably lower percentage than either the refined oil or 
the kernel oil. The general physical properties are practically the 
same. No marked differences are noted in the melting points or in the 
neutralization value. Judging from the neutralization values it is 
very probable that the major part of the solid acids consists of stearic 
acid, which theoretically has a neutralization value of 197.5. The 
melting point of pure stearic acid is 69° C, but the commercial article 
is often contaminated with other acids and has been known to melt as 
low as 56° C. The low melting point of the solid acids in the cherry 
oils may be attributed to impurities, as the determinations were made 
without any attempt at purification. 

It may safely be assumed, therefore, that the solid acids of cherry 
oils consist chiefly of stearic acid, with possibly a slight admixture 
of palmitic acid, which has a neutralization value of 219 and a 
melting point of 62° C. 

The liquid acids comprise the largest portion of the oils. The crude 
oil from the pits was found to contain 84 per cent, the refined oil 83.2 



14 BULLETIN 350, U. S. DEPARTMENT OF AGRICULTURE. 

per cent, and the kernel oil 82.8 per cent. From the physical proper- 
ties it is very probable that the bulk of the liquid acids consists of oleic 
acid. The specific gravity of pure oleic acid is reported as 0.895 at 
25° C. and the index of refraction at the same temperature as 1.4603. 
These figures agree very closely with those recorded in Table V. The 
descriptions of the acids obtained are also very similar to the descrip- 
tion of official oleic acid, which is described as } T ellowish or brownish 
yellow in color, with a peculiar lardlike odor and taste. 

That the bulk of the liquid acids consists of oleic acid is further 
substantiated by the close agreement of the iodin value of these acids 
as found in the cherry oils and the iodin value of commercial oleic 
acid. Although the iodin value of the pure acid is 90, some oleic acids 
of commerce have values as high as 100 to 110. 

The somewhat low neutralization values found in the cherry oils 
are probably due to slight changes in the fatty acids, as it is well 
known that these are apt to decompose. 

In approximating the composition of cherry oil, only the kernel oil 
was considered. It was found that this oil consisted of 8.96 per cent 
of solid acids, which were composed of stearic acid with a possible 
trace of palmitic acid. Since the glyceric! stearin contains 95.73 per 
cent of stearic acid, it was found by calculation that the oil contained 
9.36 per cent of stearin. The original oil consisted of 82.8 per cent of 
liquid acids, which, calculated as oleic acid and reduced to terms of 
olein (olein contains 95.7 per cent oleic acid), corresponds to 86.5 per 
cent of the glycericl olein. 

A brief summary of the results obtained by the chemical examina- 
tion indicates, therefore, the following approximate composition of 
cherry kernel oil: Olein, 86.5 per cent; stearin, including a possible 
trace of palmitin, 9.36 per cent; the remaining portion of the oil con- 
sists of smaller amounts of free acids, volatile acids, and unsaponifi- 
able matter. 

REACTION OF THE OIL TOWARD REAGENTS. 

Color reactions are frequently applied to fixed oils, although per- 
haps more for the purpose of detecting adulterations than for deter- 
mining the quality. Certain reagents produce characteristic color 
reactions; therefore, when it is desired to compare related oils it is 
often expedient to ascertain the behavior of the oils toward reagents. 
Since this investigation deals with an oil which is closely related to 
several well-known commercial oils, a number of color reactions were 
therefore determined and comparison was made with the color reac- 
tions obtained from the affiliated oils extracted by means of ether in 
this laboratory. The results are presented in Table VI. 



THE UTILIZATION OF CHEERY BY-PRODUCTS, 



15 



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16 BULLETIN 350, U. S. DEPABTMENT OF AGRICULTURE. 

The color reactions obtained by the use of the various reagents 
show some differences, yet they bear a certain fixed relationship, 
differing usually only in intensity. From the color reactions pro- 
duced it can not be stated that the quality of one oil is superior to 
that of an}^ other, but a close relationship is clearly obvious. The 
test with fuming nitric acid and water, as prescribed in the United 
States Pharmacopoeia x for the expressed almond oil, depends upon 
the formation of a polymerized solid compound with the olein of the 
oil. This test emphasized most strongly the similarity of cherry- 
kernel oil to official almond oil and also to the other related oils. 

Inasmuch as almond kernels and peach and apricot kernels yield 
fixed oils of commercial value, attention is called to the close resem- 
blance of cherry oil to these oils. Careful inspection of the chemical 
*;nd physical properties has shown that, although it is not identical 
with either almond, peach, or apricot oil, it is not fundamentally 
different from any of these. The variations observed may not be 
due wholly to difference in composition, since often fixed oils from 
the same source possess varying properties. The condition of the 
material from which the oil is extracted and also the seasonal factors 
are influential in affecting the ultimate quality of an oil. 

Because of this close relationship, cherry-kernel oil should there- 
fore be adapted to the same uses for which the other oils are 
employed. 

AVAILABLE QUANTITY OF THE FIXED OIL. 

Of first importance in connection with the possible commercial 
utilization of waste cherry pits is the available quantity of the mate- 
rial. A conservative estimate of a normal year's output from the 
red sour cherries is 1,600 tons. By actual experiment it was found 
that 28 per cent of the pits consists of kernels. On this basis there 
would be available annually 448 tons of kernels. By the use of mod- 
ern hydraulic presses this quantity of kernels should yield 134 tons 
of fixed oil, or 268,000 pounds. In addition to this, there is also an 
annual accumulation of about 650 tons of pits from the imported 
cherries. Only 9 per cent of these pits was found to consist of 
kernels. The quantity of kernels available from this source, there- 
fore, would be 58.5 tons. On extraction with ether these kernels 
yielded 50 per cent of oil. Subjected to hydraulic pressure about 45 
per cent would be obtainable, which would give approximately 26 
tons, or 52,000 pounds of oil. Therefore, the total quantity of fixed 
oil available from the annual accumulation of cherry pits, both 
domestic and imported, would be 160 tons, or 320,000 pounds. 

1 The Pharmacopoeia of the United States . . . Eighth decennial revision, p. 307. Phil- 
adelphia, 1907. 



THE UTILIZATION" OF CHERRY BY-PRODUCTS. 17 

USES OF THE FIXED OH. 

Cherry oil should be adapted to all purposes for which almond, 
peach, or apricot oil is used. Almond oil is used chiefly in pharma- 
ceutical preparations, and the demand is considerable. Therapeuti- 
cally, peach and apricot oils are as efficient as almond oil. Peach and 
apricot oils have recently been manufactured in California for use as 
edible oils and are said to excel olive oil in flavor and taste. 

VALUE OF THE FIXED OH. 

The value of cherry oil would naturally depend upon its use and 
the demand for oils of this character. The importation of sweet and 
bitter almond oil for the year ended June 30, 1914, was 38,586 pounds, 
valued at $36,620. 1 The price of peach-kernel oil has ranged from 22 
cents a pound in 1913 to 45 cents in 1915. No data are available re- 
garding the extent of the importation of this oil or of apricot oil, 
although it is known that large quantities are imported annually. 

VOLATILE OIL. 

METHOD OF EXTRACTION. 

The volatile oil does not exist as such in the kernels, but is the 
result of glucosidal hydrolysis, the glucosid amygdalin reacting with 
the ferment emulsin in the presence of water. It is one of the com- 
paratively few oils which are obtained only after chemical reaction 
has taken place. 

The first step necessary in extracting the volatile oil from the 
kernels was to produce the reaction between the glucosid amygdalin 
and the ferment emulsin under conditions which would insure a 
complete formation of the oil. This was best . accomplished by the 
method formulated in a previous investigation, 2 which in substance 
is as follows: To one part of the ground kernels or press cake add 
two or three parts of lukewarm water, and macerate with frequent 
agitation for about one hour, after which pass steam, under slight 
pressure, into the mixture and distill until approximately four parts 
of distillate are obtained. The volatile oil, which is heavier than 
water, will separate on the bottom of the receiving vessel. The 
upper aqueous distillate, which is saturated with the oil in solution, 
can be drawn off and subjected to distillation by the direct application 
of heat. This process can be continued until the full yield of oil is 
obtained. 

1 U. S. Department of Commerce. Foreign Commerce and Navigation of the United 
States for the Year Ending June 30, 1914, pp. 820-821. Washington, 1915. 

2 Rabak, Frank. Peach, apricot, and prune kernels as by-products of the fruit industry 
of the United States. U. S. Dept. Agr., Bur. Plant Indus. Bui. 133, p. 24, 1908. 



18 BULLETIN" 350, U. S. DEPARTMENT OF AGRICULTURE. 

In order to obtain the maximum yield it is very important that the 
maceration of the ground material be made with lukewarm water, 
as the reaction between the constituents, with the formation of oil, 
takes place most expeditiously at that temperature. It is also neces- 
sary to conduct the maceration in a closed vessel, preferably in the 
still itself, in order to avoid the loss of oil by evaporation. 

As a preliminary experiment, a quantity of ground pits was treated 
according to this method and distilled in a still consisting essentially 
of a still body and a condenser. Live steam was passed into the 
macerated mixture, and the distillate collected in a receiving vessel 
of glass, from which the aqueous distillate was easily decanted. The 
oil accumulated on the bottom, and the final separation was made by 
means of a separatory funnel. After cohobation of the distillate, 
which consists in redistilling by direct application of heat, the yield 
of oil was found to be 0.1 per cent. 

By careful manipulation a yield of 0.95 per cent of volatile oil was 
obtained from the press cake which remained after the extraction 
of the fixed oil from the kernels. This is equivalent to nearly 1 pound 
of oil from every 100 pounds of press cake. 

It is recommended that the volatile oil be extracted from the ker- 
nels rather than from the pits direct, both from an economical stand- 
point and from the ease of manipulation, since much loss is avoided 
in working with the smaller volume of material in the form of the 
press cake than with the much larger bulk of ground pits. 

PHYSICAL AND CHEMICAL PROPERTIES OF THE VOLATILE OIL. 

The physical and chemical properties of the volatile oil were deter- 
mined and together with the yields were tabulated with other kernel 
oils, which included several market samples of bitter-almond oil. 
According to the United States Pharmacopoeia, bitter-almond oil is 
designated as being derived from bitter almonds and " other seeds 
containing amygdalin." 1 Cherry kernels contain amygdalin, and 
cherry oil should therefore belong to the same class as bitter- 
almond oil. 

The data obtained from the physical and chemical examination of 
the volatile oils are presented in Table VII. 

An examination of Table VII shows that the yield of cherry oil 
was somewhat less than that of the other oils. This is explained by 
the fact that the kernels used in the experiment were from pits which 
had been in the laboratory for a considerable length of time and had 
undoubtedly deteriorated. The yield of oil from fresh kernels would 
very probably be higher. However, the yield obtained was sufficient 
to justify the use of cherry kernels for the production of oil. 

1 The Pharmacopoeia of the United States . . . Eighth decennial revision, p. 306. Phil- 
adelphia, 1907. 



THE UTILIZATION OF CHERRY BY-PRODUCTS. 



19 



Table VII. — Yield, physical properties, and chemical composition of the volatile 

oils from various fruit sources. 



Source of oil. 



Cherry kernels.. 

Cherry pits 

Peach kernels 4 . . 

Apricot kernels 4 

Prune kernels 4 . 
Bitter almonds 4 



B i 1 1 e r - almond oil 
(market sample 2 
years old). 

B it ter- almond oil 
(market sample 1 
year old). 

Benzaldehyde (sev- 
eral years old). 



Yield 
from 
press 
cake. 



Per cent. 
0.95 



.10 
1.17 

1.33 

.71 
1.15 



Color. 



Pale straw. . 



Golden yel- 
low. 

Pale straw . . 



Straw. 



Faint straw . 
do 

Golden 

Pale yellow. 



Deep yel- 
low. 



Odor. 



Pleasant, 
strong, bit- 
ter-almond - 
like. 

Agreeable 
charac- 
teristic. 

Bitter-almond- 
like, some- 
what irritat- 
ing. 

Aromatic , 
almond-like. 

Strong benzal- 
dehyde. 

Less aromatic 
(fainter than 
above). 

Characteristic, 
mellow. 

Strong and 
penetrating. 

do 



Taste. 



Sweet and 
very pun- 
gent. 

Sweet, strong, 
pungent. 

Sweet and 
pungent. 



Sweet and in- 
tensely pun- 
gent. 

Sweet and 
pungent. 

Sweet, less 
pungent. 

Very pungent. 



Sweetish pun- 
gent. 

Very sweet, 
pungent. 



Spe- 
cific 
gravity 
at24C. 


HCn.i 


1.050 


Per ct. 
4.21 


1.012 


7.94 


1.068 


2.20 


1.080 


2.05 


1.050 


1.75 


1.056 


4.80 


1.059 


2.57 


1.058 


2.12 


1.062 


513.7 



Benzal- 
de- 
hyde.* 



Per ct. 
3 81.53 



67.95 
73.1 

3 88. 7 

76 
62 

78.45 

80.6 

77.5 



1 Assayed according to the volumetric method of the Pharmacopoeia of the United States, Eighth 
decennial revision, p. 306. Philadelphia, 1907. 

2 Assayed by the sodium bisulphite method. The Pharmacopoeia. Loc. cit. 
8 Assayed immediately after distillation. 

* Rabak, Frank. Peach, apricot, and prune kernels as by-products of the fruit industry of the United 
States. U. S. Dept. Agr., Bur. Plant Indus. Bui. 133, p. 23, 25, 1908. 
5 Benzoic acid. 

The physical properties do not differ greatly ; in fact, they nearly 
coincide with those of the other oils. In hydrocyanic-acid content the 
cherry oil was found to be somewhat higher than in the other oils, but 
it was nearly within the limits of the Pharmacopoeia, which requires 
not less than 2 nor more than 4 per cent. The benzaldehyde content, 
which, because of its instability under ordinary means of preservation 
fluctuates noticeably in this class of oils, compares favorably with the 
other kernel oils. The pharmacopceial requirement with regard to 
benzaldehyde content is that it shall not be less than 85 per cent. The 
benzaldehyde content of the cherry oil, although lower than the 
requirement, is not as low as in the two samples of bitter-almond oil 
purchased in the open market, both of which were slightly deficient 
on account of deterioration, which was undoubtedly due to the age of 
the oils. This deterioration in benzaldehyde content is more or less 
rapid, because of the ease with which it oxidizes to benzoic acid. The 
sample of benzaldehyde examined illustrates the change which takes 
place under ordinary conditions. The sample, which originally was 
a pure compound, after standing for several years shows but 77.5 per 
cent of benzaldehyde. The free acidity, calculated as benzonic acid, 
was 13.7 per cent. The benzaldehyde content bears a direct relation- 
ship to the specific gravity ; the higher the benzaldehyde content the 
lower the specific gravity. 



20 BULLETIN 350, U. S. DEPARTMENT OF AGRICULTURE. 

On the whole, the properties of cherry oil compare very favorably 
with the commercial oils, considering the many unfavorable factors 
which unavoidably enter into the distillation on a laboratory scale, 
and it may therefore be considered that for all practical purposes 
this oil is equal to the oil of bitter almonds and the other kernel oils. 

AVAILABLE QUANTITY OF THE VOLATILE OIL. 

Approximating the total available quantity of kernels from the 
domestic cherries at 448 tons and deducting 30 per cent, the quantity 
of fixed oil capable of being extracted, there would remain about 
314 tons of press cake. It has been shown that 0.95 per cent of vola- 
tile oil can be obtained from the press cake, and there would result, 
therefore, practically 3 tons of volatile oil, or 6,000 pounds. 

USES OF THE VOLATILE OIL. 

Bitter-almond oil, aside from its use for medicinal purposes, finds 
a widespread use in the manufacture of perfumery and confectionery. 
In the perfumery trade the demand is for the genuine oil rather than 
for the synthetic article, as the odoriferous properties are much finer 
and more agreeable. The importation of bitter-almond oil for the 
year ended June 30, 1914, reached a total of 7,525 pounds, valued at 
$21,954, 1 showing that the demand for this oil is keen. For some 
time prior to August, 1914, the price of bitter-almond oil has shown 
a gradual increase, the wholesale market quotations ranging from 
$3.25 to $4.75 in 1910 2 to $3.50 to $6.50 during the first six months of 
1914. 2 Since then the price has risen rapidly, due apparently to lack 
of importations. At the present time (January, 1916) the oil is 
quoted at $9.25 to $11 a pound. 3 

VALUE OF THE VOLATILE OIL. 

Assuming that 6,000 pounds of volatile oil can be produced annually, 
the gross income from the total available output of kernels, calculated 
at the minimum price quoted at the present time, would be $46,500. 
Therefore it would seem reasonable to suppose that the production 
of volatile oil from waste cherry pits should meet with favorable 
attention as a means of converting the now useless waste into a 
source of profit. 

CHERRY-KERNEL MEAL. 
CHEMICAL CONSTITUENTS. 

After distilling the volatile oil from the press cake, the residue 
which remained consisted of a mushy mass. The moisture was re- 

a U. 8. Department of Commerce. Foreign Commerce and Navigation of the United 
States for the Year Ending June 30, 1914, p. 821. 'Washington, 1915. 

2 Oil, Taint, and Drug Reporter. 

3 Oil, Paint, and Drug Reporter, v. 89, no. 3, p. 40. 1916. 



THE UTILIZATION" OF CHERRY BY-PRODUCTS. 



21 



moved from this mass partly by pressure and partly by drying, after 
which the dried mass was ground to a meal. Upon examination, 
the meal was found to contain 1.06 per cent of moisture; 3.94 per 
cent of ash ; 13.1 per cent of ether extract ; 30.87 per cent of protein ; 
8.9 per cent of crude fiber, and 42.13 per cent of nitrogen-free extract. 
In order to interpret these results with regard to the value of the 
meal as a stock food, in which it probably would find its chief use, 
comparison of the various constituents was made with those of several 
feeding stuffs as recorded by Henry. 1 The comparison is shown in 
Table VIII. 



Table VIII. — Cherry-kernel meal compared with various commercial 

stuffs. 


feeding 




Constituents (per cent). 


Feeding stuff. 


Moisture. 


Ash. 


Protein. 


Nitrogen- 
free ex- 
tract. 


Fiber. 


Ether ex- 
tract. 


Cherry-kernel meal 


1.06 

11.3 

9.8 
7.0 
10.3 
10.4 
10.8 
10.7 
10.0 
7.4 
15.0 


3.94 

5.9 
5.5 
6.6 
5.9 
4.3 
6.7 
4.9 
7.9 
8.8 
1.4 


30.87 

42.7 
33.9 
45.3 
19.7 
16.8 
32.8 
47.6 
31.2 
36.7 
9.2 


42.13 

28.1 
35.7 
24.6 
38.7 
35.0 
27.1 
23.7 
30.0 
17.3 
68.7 


8.9 

6.0 

7.3 

6.3 

14.4 

24.0 

13.5 

5.1 

11.3 

3.8 

1.9 


13.1 


Soy-bean cake 


6.0 


Linseed meal 


7.8 


Cottonseed meal 


10.2 


Coconut cake 


11.0 


Palm-nut cake 


9.5 


Sunflower-seed cake 


9.1 


Peanut cake 


8.0 


Rape-seed cake 


9.6 


Sesame-oil cake 


26.0 


Corn meal 


3.8 







The low percentage of moisture in the cherry-kernel meal is due 
to the fact that the material was dried just before the determination 
was made. The percentage of ash is somewhat lower than in any of 
the other feed cakes, with the exception of corn. 

From the standpoint of food value the most important constituents 
are the ether extract, consisting largely of fat and other soluble con- 
stituents; the protein, consisting of nitrogen compounds; and the 
nitrogen-free extract, which includes soluble carbohydrates, such as 
sugar, starch, gums, etc. The meal is considerably richer in ether 
extract than any of the foods enumerated, with the exception of 
sesame- oil cake. In content of nitrogen-free extract it excels nearly 
all. The protein content, also, compares very favorably with the 
more important feeding stuffs of commerce. The percentage here 
given is doubtless below the actual percentage of soluble carbohy- 
drates, due to the partial extraction of the water-soluble compounds 
of the meal by the water contained in the still after distillation. To 
illustrate : It was found that the water extract from the distillation 
of a quantity of ground pits, after evaporation to dryness, consti- 
tuted 6.7 per cent of the original ground material. The solid extract 
after powdering was chocolate brown in color, with a rather pleasant 



1 Henry, W. A. Feeds and Feeding 



ed. 10, p. 566-567. Madison, Wis.. 1910. 



22 BULLETIN 350, U. S. DEPARTMENT OF AGRICULTURE. 

taste suggesting roasted grain. This extract was readily soluble in 
water. The protein content was found to be 33.93 per cent. The 
utilization of this waste water-soluble extract by evaporation with 
the meal left in the still would add much to the nourishing properties 
of the meal. The fiber content, although not high in comparison 
with some of the other meals, was augmented by the presence in the 
kernels, before grinding, of particles of the pits which escaped sepa- 
ration in the cracking process. 

AVAILABLE QUANTITY, USES, AND VALUE OF CHERRY- KERNEL MEAL. 

Roughly estimated, the total available quantity of meal which 
would result after extracting the oil would be about 300 tons from 
the domestic cherries and 30 tons from the imported cherries. 

The utility of the meal, as shown by its composition, should be 
similar to that of the general class of oil cakes now sold on the 
market for stock foods. 

Regarding the commercial value only an estimate can be made. 
Based on the current prices of linseed meal, which is about $39 per 
ton, the estimated money value of the yearly output of cherry-kernel 
meal would be about $12,870. 

COMMERCIAL PRODUCTS OBTAINABLE FROM CHERRY JUICE. 

Attention has already been called to the large quantity of juice 
which accumulates during the operation of pitting cherries. The 
juice is bright red in color, with the odor and taste of cherries. 
Using the sugar and acid content as a basis for investigation, several 
experiments were conducted, with a view to preparing products 
which might be of commercial value. 

ALCOHOL FROM CHEERY JUICE. 

In order to convert the cherry juice into alcohol, a cake of com- 
pressed yeast was added to 1 kilo of filtered juice and the mixture 
kept at 30° C. for a period of 24 hours, with occasional agitation. 
After this period, fermentation had completely ceased. The mixture 
was then filtered, neutralized with milk of lime, and distilled. A 
small quantity of phosphoric acid was added to the distillate and a 
second distillation made. The alcohol obtained was deodorized by 
the addition of potassium permanganate and again distilled. By this 
method it was calculated that 4.36 per cent of absolute alcohol, or 
4.6 U. S. P. alcohol (95 per cent by volume), could be prepared from 
the waste juice. 

SIRUP FROM CHERRY JUICE. 

For the preparation of sirup, a quantity of the filtered juice was 
evaporated in vacuo after previously neutralizing the acidity with 
milk of lime. The calcium salts of the acids were filtered from the 



THE UTILIZATION" OF CHERRY BY-PRODUCTS. 23 

hot sirup by means of vacuum filtration. This procedure was carried 
on twice during the concentration of the juice. The yield of sirup 
obtained was about 20 per cent. The calcium salts (probably con- 
sisting largely of calcium malate) after drying resulted to the extent 
of 1.35 per cent. The sirup obtained was dark brown in color, with a 
pleasant, sweet, slightly tart taste. 

The specific gravity at 24° C. was 1.34. Assayed gravimetrically by 
means of Fehling's solution the content of reducing sugars was found 
to be 43 per cent and the total sugars 52.1 per cent. 

The free acidity was determined by titration with N/10 potassium 
hydroxid V. S. and calculated as malic acid by means of the malic- 
acid factor (1 c. c. N/10 KOH= 0.0067 gm. malic acid). The sirup 
was found to contain 1.3 per cent of malic acid. 

These properties of the sirup are most variable and are subject to 
fluctuation, depending to a great extent upon the consistency to which 
the sirup is evaporated. The greater the concentration the higher 
the percentage of the important constituents. 

JELLY FEOM CHEEKY JUICE 

For the preparation of jelly the cherry juice was concentrated with 
cane sugar (1 pound of sugar to 1,200 c. c. of juice) in a vacuum to a 
sirupy consistency. Purified gelatin was then added (one-half ounce 
of gelatin dissolved in one-half pint of water) and the mixture set 
aside in a cool place. The resulting jelly was wine red in color, with 
a fruity odor and a very pleasant tart taste. 

Although this process is a very crude one, it shows the possibility 
of converting the juice into a product which is decidedly wholesome. 
Other processes of preparing jelly from juices of this nature by the 
use of pectin or parings from fruits which are rich in pectin would 
doubtless be productive of even more promising results. 

Calculated with the amount of sugar added it was found that about 
81.6 per cent of jelly could be prepared from the juice. 

AVAILABLE QUANTITY, USES, AND VALUE OF THE ALCOHOL, SIRUP, AND 

JELLY FROM CHERRY JUICE. 

The prospect of profitably converting the juice into commercially 
useful products would depend largely upon the available quantity. 
As previously stated, approximately 105,000 gallons of juice result 
from the pitting process. The alcohol production from this quantit}^ 
of juice would be about 5,000 gallons. The usefulness and commercial 
value of alcohol is well known and needs no further comment. 

The quantity of sirup capable of being manufactured from the 
total available juice, calculating the yield of sirup as 20 per cent, 
would be 21,000 gallons. The usefulness of the sirup as a household 
commodity can hardly be questioned. It is also possible that it could 



24 



BULLETIN" 350, TJ. S. DEPARTMENT OF AGRICULTURE. 



be reapplied to the canning of cherries, much as the sirup from pine- 
apple waste is at present utilized. The value must necessarily be de- 
terminated by the uses to which it can be put and the demand created 
thereby. Its pleasant taste and agreeable flavor should create a de- 
mand for the product as a table commodity. 

The total quantity of jelly which could be manufactured from the 
juice available annually would approximate 85,680 gallons. The 
actual value of this quantity of jelly can not be accurately estimated, 
but it can safely be assumed that a considerable margin of profit would 
result after deducting the expense of manufacture. 

SUMMARY. 

To briefly recapitulate the results of the foregoing investigation, 
it is shown that the waste products from the cherry industry can be 
reduced to a number of valuable products : 

(1) The fixed oil, which is perhaps the most important product, is, in its prop- 
erties and general characteristics, so closely related to the commercial oil of 
almonds that it is placed in an important position with respect to usefulness and 
value. The oil expressed from the fresh kernels is quite similar to almond oil 
and its use as an article of commerce, applied along pharmaceutical and thera- 
peutical lines, or as a condimental oil, or even for soap-making purposes, should 
be assured. 

(2) The volatile oil which can be produced from the press cake after the fixed 
oil has been extracted is practically identical with the oil of bitter almonds, thus 
rendering its usefulness the same in every way as that of bitter-almond oil. 

(3) The meal, which is the final residue, has been shown to possess nourish- 
ing properties, much the same as those of the more common feeding stuffs on the 
market. 

(4) The juice has been shown to be capable of being transformed into alcohol, 
sirup, or jelly, and it is reasonable to assume that there should be a demand for 
such products. 

The success of an undertaking involving the by-products in question 
would depend largely upon the efficacy of any proposed system where- 
by the products could be manufactured. Since the waste as it accu- 
mulates is not confined to any particular section, perhaps the most 
feasible method would be to accumulate the waste at some central 
point. The most convenient plan then would be to conduct the man- 
ufacture on a cooperative basis, much as the present system of co- 
operative creameries is conducted, whereby the cream produced in any 
dairy section is conducted to a central plant where the products are 
manufactured. 

While the object of this investigation is principally to point out the 
possibilities existing in the cherry by-products, it is hoped that the 
information contained herein will serve as an incentive to the proper 
disposition of these waste products, with their ultimate reduction 
into products of commercial utility and value. 

LIBRARY OF CONGRESS 

WASHINGTON ! GOVERNMENT PRINTING OFFICE '. 1916 




I.' 



012 822 382 4 



LIBRARY OF CONGRESS 



012 822 382 4 



LIBRARY OF CONGRESS 



012 822 382 4 



